The Austin weekly statesman. (Austin, Tex.) 1883-1898, 1887-12-15

| ~ o'Si Uio Iuree sub Archn.
ID order 10 transfer the weight Of ~
superintendent wall from the insnfao,.u :.
piers below to the abutments ON a;t.
side. This change subjected the abntmsusls
OF the relieving arch to weight os ~
tots per square foot, whilst it Removes
load of about double that amount from :,
piers between the sub arches. Fron,
careful examination of all the strrctn..
and economic points involved. wa ~
firmly of the opinion that this chanoa ~
construction was entirely judicious. Nsvs.
theless, when the construction of the don.
wall had proceeded nearly to the ton ~
the interior colonade, a slight crack, about
the width of an ordinary pencil lima q,
less than the sixt- enth Of an inch ua.
observed on the intrados and on both
faces of the relieving arch.
The further progress of the brickvo,L
or the dome was then promptly suspended
by the commissioners and superintendent
NO change or enlargement of the cracL
seems TO nave occurred since il was
hrst noticed, nor was any of the bricL.
work around it shattered. There certa;plv
has been no increase in the size Of The
crack during the past week.
This being the condition of affairs m
our arrival, we Immediately made a care
ful instrumental examination to ascertain.
| First-If the foundations to the abnt-
nents of the relieving arch had settled
Second-If the masonry of the abut-
ments, from the foundation to the sprin,
line of the arch, had been compressed; and
thlrd-If the abItments had spread from
the lateral thrust of the arch. We have en-.
tlrely satisfied ourselves that failure has
not ocourrei In any of these directionsand
that the slight fracture of the arch ba,
resulted only from a movement taking
place under the adjustment of equilibrium
before the masonry had set. Sucb an
occurrence might reasonably be produced
| by p1llng heavy mass of green brick
work upon newly built arch with undue
haste. 1t is also probable that, while the
entire arch was doubtless under consider
able and unstable load, the immediate
cause of the appearance of the crack in
| this particular place was due to the hard
| driving into the face of the arch of 2x4
inch wedge, helically shaped, to which the
| wooden cornice brackets were to be at
| tached. We think that these causes
satisfactorily explain defect which i'm
pairs only the appearance but not in any
| degree the safety of the dome. We do
| not believe, particularly if the recommends
tlons we hereinafter make are carried
out, that any increase in this crack is to
| be apprehended, and neither will it be
| observable after the completion of the
| building. Nevertheless as the relieving
arch was not part of the original de-
| al ga ha M fha lot
| shafts, now serving for its abutments,
were not designed for this purpose, and
although they have shown no signs of
failure, yet we have thought it prudent to
include, in the subsequent recommends
lions, the insertion of strong iron tIe-rods
at the spring line of the arch.
We then continued our examination
throughout the iron work of the dome.
Whatever rigidity may be lost by such
| omission of brickwork as we have recon-
mended below, will be recovered and
even increased by the introduction of ad
ditional iron bracing. In fact, we
would have preferred, if possible,
to make this substitution Of
iron bracing for brick at an earlier
stage in the progress of the dome wall, as
brick walls SO cut into piers by openings
are dependent upon the iron for Stiffness
| rather than the iron upon the brick work
The design for the construction of the
lantern surmounting the dome we con-
slider particularly deficient in strength.
We have, therefore, recommended the in
PRODUCTION of complete system of iron
bracing throughout this part of the build
ing.
We are now prepared, after full per
sonal examination of the building, to-
gether with the contract, plans and spe-
cifications for same, and after free con-
ference with the commissioners, the SUI
perlntendent of construction, the con-
tractor and others familiar with the
structure, all of whom have extended TO
US every facility for obtaining accurate
information of every part of the work, TO
make the following recommendation
concerning the completion Of the dome
They have been, to some extent, antlcl'
pated by the capitol commissioners and
the superintendent of construction IN
! their reports heretofore made to the cap
| itol board. We recommend, therefore;
First-That the brick work of the dome
between the abutments of the relieving
main at its present height.
Second-Thst on either side OF this
space, between the abutments, the dome
wall be rscked up with quarter brlck
Offsets or at 60 degrees to the top OF Inc
balcony floor beams; and that this waI',
from a line two feet below the said noor
beams, be laid in mortar of one OF &C.
ment to one of sand.
Third-That two tie rods, each !Ao
inches, or of round iron of equal section
with all parts and connections OF equai
strength, be built in below the spring Inc
of the arch, extending from venn
tilsting shaft to ventilating shsis
on either side, where the ends shall 90
secured by washer plate foot by leo'
and inches thick, well bedded, and three
inch nuts.
Fourth-That Immediately above inc
top of the brick work, as before describes
the dome ribs shall be connected on INC
out and inside by horizontal bands u
7-inch l beams. These beams shall nave
the fanges cut from one side, SO as 70 Nv
closely around the rib fsDges. The tbs
of these beams shall be fastened to tne
flanges of the ribs with four rivets' nv
joints they shall lap the full width OF slo
rib hange, or inches. Wherever rlVe''
now in the rib fange interfere with con
tact of the webs of the beams with Ine
ribs, these rivets shall be removed and 10.
placed with other rivets, through the Same
Al 3I,a xuah of the beambs